A056465 - OEIS

%I #10 Sep 29 2019 11:10:11

%S 0,0,0,0,0,0,24,24,240,240,1560,1560,8400,8376,40824,40800,186480,

%T 186240,818520,818280,3497976,3496440,14676024,14674440,60780720,

%U 60772320,249401640,249393480,1016542800,1016501736,4123173624,4123132800,16664093400,16663908480

%N Number of primitive (aperiodic) palindromes using exactly four different symbols.

%D M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]

%H Andrew Howroyd, <a href="/A056465/b056465.txt">Table of n, a(n) for n = 1..200</a>

%F a(n) = Sum_{d|n} mu(d)*A056455(n/d).

%Y Column 4 of A327873.

%Y Cf. A056455, A056460.

%K nonn

%O 1,7

%A _Marks R. Nester_

%E Terms a(31) and beyond from _Andrew Howroyd_, Sep 28 2019